What does conspiracy mean?
A conspiracy is a secret plan devised by two or more people to carry out an unlawful or harmful act, such as fraud, treason, or violence. The word is central to legal language, where 'conspiracy' names a specific offence: merely agreeing with others to break the law constitutes the crime, even if the plan is never carried out. Beyond the courtroom, conspiracy is widely used in journalism and political discourse to describe covert plots within governments, corporations, or other organizations. It also appears in the familiar phrase 'conspiracy theory', which refers to an explanation of events that blames a hidden group working in secret — a usage that usually signals skepticism rather than endorsement. The word always carries negative connotations, implying deceit, betrayal, and illicit cooperation. Related forms include the verb 'conspire', the nouns 'conspirator' and 'co-conspirator', and the adjective 'conspiratorial', which describes secretive, plot-like behavior.
A secret plan by two or more people to do something unlawful or harmful; also, in law, the offence of agreeing with others to commit such an act.
"The court found them guilty of conspiracy to defraud investors."
In criminal law, the agreement itself is the crime — the planned act need not have been attempted or completed.
A belief that significant events are secretly caused by a powerful group acting in concert, especially when such an explanation lacks evidence (as in 'conspiracy theory').
"His account of the moon landing was pure conspiracy, repeated without a shred of evidence."
This extended usage is almost always pejorative and most commonly appears in the fixed phrase 'conspiracy theory'.
Standard English plural: the '-y' becomes '-ies' after the consonant c.
"Historians have documented several conspiracies against the Tudor monarchy."
Shakespeare put it best in Julius Caesar: "O conspiracy, sham'st thou to show thy dangerous brow by night" — the word has been naming secret plots for over four centuries.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of conspiracy
Conspiracy comes from the Latin verb 'conspirare', meaning literally 'to breathe together', formed from 'con-' (together) and 'spirare' (to breathe). The image was of people acting in unison, as if breathing as one, which came to signify plotting in agreement. The term entered English via Old French in the late medieval period, and by the early modern era it was well established in both political and legal contexts. It shares its Latin root with words such as inspire, respire, transpire, and spirit.
Related word forms
How conspiracy is actually used
Conspiracy carries strongly negative connotations and is common in legal, journalistic, and political contexts. In everyday speech it often appears in the compound 'conspiracy theory', which typically implies skepticism about the claim being described. As a count noun it takes standard plurals ('conspiracies').